Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre-and postinfection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality.

To augment HIV-1 pox-protein vaccine immunogenicity using a next generation adjuvant, a prime-boost strategy of recombinant modified vaccinia virus Ankara and multimeric Env gp145 was evaluated in macaques with either aluminum (alum) or a novel liposomal monophosphoryl lipid A (MPLA) formulation adsorbed to alum, ALFA. Binding antibody responses were robust and comparable between arms, while antibody-dependent neutrophil and monocyte phagocytotic responses were greatly enhanced by ALFA. Per-exposure vaccine efficacy against heterologous tier 2 SHIV mucosal challenge was 90% in ALFA-adjuvanted males (P = 0.002), while alum conferred no protection. Half of the ALFA-adjuvanted males remained uninfected after the full challenge series, which spanned seven months after the last vaccination. Antibody-dependent monocyte and neutrophil phagocytic responses both strongly correlated with protection. Significant sex differences in infection risk were observed, with much lower infection rates in females than males. In humans, MPLA-liposome-alum adjuvanted gp120 also increased HIV-1-specific phagocytic responses relative to alum. Thus, next-generation liposome-based adjuvants can drive vaccine elicited

Nutrient utilization and energy metabolism are critical for the maintenance of cellular homeostasis. A mutation in the C9orf72 gene has been linked to the most common forms of neurodegenerative diseases that include amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we have identified an evolutionarily conserved function of C9orf72 in the regulation of the transcription factor EB (TFEB), a master regulator of autophagic and lysosomal genes that is negatively modulated by mTORC1. Loss of the C. elegans orthologue of C9orf72, ALFA-1, causes the nuclear translocation of HLH-30/TFEB, leading to activation of lipolysis and premature lethality during starvation-induced developmental arrest in C. elegans. A similar conserved pathway exists in human cells, in which C9orf72 regulates mTOR and TFEB signaling. C9orf72 interacts with and dynamically regulates the level of Rag GTPases, which are responsible for the recruitment of mTOR and TFEB on the lysosome upon amino acid signals. These results have revealed previously unknown functions of C9orf72 in nutrient sensing and metabolic pathways and suggest that dysregulation of C9orf72 functions could compromise cellular fitness under conditions of nutrient stress.